The present invention relates to a new and improved construction of a device for the withdrawal of blood, especially for the withdrawal of blood from arteries, which device comprises a puncture needle.
For diagnostic purposes, especially for blood gas analysis, it is necessary to anaerobically remove samples from arteries. Removal of blood from arteries is appreciably more risky for patients and associated with rather uncomfortable consequences than the withdrawal of blood from veins. Usually there forms at the site of the puncture of an artery, after removal of the puncture needle, a hemotoma (bleeding), since the arterial blood which is under pressure flows out through the puncture channel penetrating the artery wall into the neighbouring tissue for such length of time until the counter pressure in the tissue closes the puncture channel or track in the arterial wall. Particularly with repeated punctures, as required for blood gas analysis during the intensive treatment of patients, there are formed large surface hematomas. Moreover, the frequent puncturing of the arterial wall with puncture needles of the type heretofore employed in practise leads to a considerable traumatization of the blood vessels.
Generally, at the present time there is accomplished arterial blood removal for blood gas analysis by means of a glass syringe and a rather massive puncture needle formed of steel. Samples of up to 10 ml are removed.
There have also become known to the art an entire spate of blood removal devices which essentially consist of an assembly of syringes and puncture needles which are packaged in a sterilized state and have in a number of different embodiments means enabling transport of the blood sample into a cooled container or receptacle.
The heretofore known blood withdrawal devices for the anaerobic removal of arterial blood samples for the blood gas analysis uniformly have the drawback that it is not possible to carry out an atraumatic or almost atraumatic puncture of an artery with such devices. Furthermore, the employed syringes have a dead space or clearance volume at the input part of the syringe which generally is filled with heparin, an additive which prevents blood coagulation.